Question

I am new to JS and encountered several new thins. For example I saw this piece of code:

function baz() {
    var x = 1;
    return {
        foo: function foo() {return ++x},
        bar: function foo() {return --x},
    };
}

var closures = baz();
alert(closures.foo(),closures.bar());

It is supposed to show a shared variable. My question is – what is being returned?

Is it simply an object with two functions foo() and bar()?
Thanks

Yotam

Answer 1

Yes, it’s “simply an object with two functions foo() and bar()”.

But this function is also declared in a closure, which means it can have this private property x which

• is visible and modifiable by both functions
• can’t be read or modified otherwise

The main differences with

var x = 1;
var closures = {
    foo: function() {return ++x},
    bar: function() {return --x},
};

is that

• x is protected by the closure creating the object
• there can be no name conflict regarding x, and the global namespace isn’t cluttered